A power device such as a diode, a power MOS transistor, and an insulated gate bipolar transistor (IGBT) needs to be provided with a device termination portion including a guard ring layer or a resurf layer, and the like, in order to ensure a breakdown voltage of the power device.
In the case where the guard ring layer or the resurf layer is provided in the device termination portion, it is difficult to shrink the width of the device termination portion. Moreover, the manufacturing processes for power devices increase when a semiconductor layer being different from the device formation region is provided in the device termination portion.